Method for towing a second vehicle by a first vehicle and electric vehicle

Abstract

Method for towing a second vehicle (204) by a first vehicle (202), the method comprising: Establishing a communication path between the second vehicle (204) and the first vehicle (202), wherein the first vehicle (202) has a first propulsion system (210); Transmitting a signal indicating an instruction to operate the second vehicle (204) via the communication path from the first vehicle (202) to the second vehicle (204); and Operating a second drive system (220) of the second vehicle (204) together with the first drive system (210) of the first vehicle (202) on the basis of the instruction to operate the first vehicle (202) and the second vehicle (204) as a series hybrid vehicle (200, 1000), characterized by the fact that The procedure further includes the use of data from the second vehicle (204) to determine a speed of the first vehicle (202) if the speed of the first vehicle (202) is not available for the second vehicle (204).

Description

INTRODUCTION

[0001] The present disclosure relates to the operation of an electric vehicle being towed by a lead vehicle, and in particular to the operation of the electric vehicle synchronously with the lead vehicle during towing.

[0002] Publication US 2023 / 0356717A1 discloses a method for towing a second vehicle by a first vehicle according to the preamble of claim 1 and an electric vehicle according to the preamble of claim 5. Publication DE 102016010573A1 discloses a related method and a related vehicle.

[0003] A vehicle being towed by another vehicle exerts a drag on the other vehicle, which can impair its operation. Therefore, it is desirable to provide a method by which a vehicle being towed can cooperate with the towing vehicle to assist in the operation of the vehicles as a single unit. SUMMARY

[0004] According to an exemplary embodiment, a method for towing a second vehicle by a first vehicle is disclosed. A communication path is established between the second vehicle and the first vehicle, the first vehicle having a first drive system. A signal containing an instruction for operating the second vehicle is transmitted from the first vehicle to the second vehicle via the communication path. The second drive system of the second vehicle is operated together with the first drive system of the first vehicle based on the instruction, in order to operate the first vehicle and the second vehicle as a series hybrid vehicle.

[0005] In addition to one or more of the features described here, the procedure also includes selecting a charging mode for charging a battery pack of the second vehicle.

[0006] In addition to one or more of the features described here, the charging mode is a fast charging mode or a hybrid charging mode that maintains a target minimum level, a hybrid maximum mode that prioritizes propulsion until the battery pack charge level has dropped to the target minimum level, and a standard charging mode that only charges when permitted.

[0007] In addition to one or more of the features described herein, the method further includes the application of braking to the second vehicle when braking is applied to the first vehicle, and / or the application of torque to the second vehicle in response to an acceleration request from the first vehicle.

[0008] In addition to one or more of the features described herein, the method also includes operating the first vehicle and the second vehicle as the series hybrid vehicle when the speed of the second vehicle is greater than a speed threshold.

[0009] The procedure also includes using data from the second vehicle to determine the speed of the first vehicle if the speed of the first vehicle is not available to the second vehicle.

[0010] In addition to one or more of the features described here, the method also includes determining a trailer coupling force between the first vehicle and the second vehicle.

[0011] According to another exemplary embodiment, an electric vehicle is disclosed. The electric vehicle comprises an electric drive system, a communication device for communicating along a communication path between the electric vehicle and a first vehicle, the first vehicle having a first drive system, the first vehicle being coupled to the electric vehicle for towing, and a processor. The processor is configured to receive a signal sent from the first vehicle to the communication device, to determine an instruction for operating the electric vehicle from the signal, and to operate the electric drive system of the electric vehicle together with the first drive system of the first vehicle based on the instruction, in order to operate the first vehicle and the electric vehicle as a series hybrid vehicle.

[0012] In addition to one or more of the features described here, the processor is also configured to select a charging mode for charging an electric vehicle battery pack.

[0013] In addition to one or more of the features described here, the charging mode is a fast charging mode or a hybrid charging mode that maintains a target minimum level, a hybrid maximum mode that prioritizes propulsion until the battery pack charge level has dropped to the target minimum level, and a standard charging mode that only charges when permitted.

[0014] In addition to one or more of the features described here, the processor is further configured to apply braking to the electric vehicle when braking is applied to the first vehicle, and / or to apply torque to the electric vehicle in response to an acceleration request from the first vehicle.

[0015] In addition to one or more of the features described here, the processor is further configured to operate the first vehicle and the electric vehicle as the series hybrid vehicle when the speed of the electric vehicle is greater than a speed threshold.

[0016] In addition to one or more of the features described here, the processor is also configured to use data from the electric vehicle to determine the speed of the first vehicle if the speed of the first vehicle is not available to the electric vehicle.

[0017] In addition to one or more of the features described here, the processor is also configured to determine a trailer coupling force between the first vehicle and the electric vehicle.

[0018] According to yet another exemplary embodiment, a series hybrid vehicle is disclosed. The series hybrid vehicle comprises a first vehicle with a first drive system, a second vehicle with a second drive system, a trailer coupling for mechanically coupling the second vehicle to the first vehicle for towing by the first vehicle, a communication path between the first vehicle and the second vehicle, and a processor in the second vehicle. The processor is configured to receive a signal sent from the first vehicle via the communication path to a communication device in the second vehicle, to determine an instruction for operating the second vehicle from the signal, and to operate the second drive system together with the first drive system based on the instruction, in order to operate the first vehicle and the second vehicle as a series hybrid vehicle.

[0019] In addition to one or more of the features described here, the processor is also configured to select a charging mode for charging a battery pack of the second vehicle.

[0020] In addition to one or more of the features described here, the processor is further configured to apply braking to the second vehicle when braking is applied to the first vehicle, and / or to apply torque to the second vehicle in response to an acceleration request from the first vehicle.

[0021] In addition to one or more of the features described here, the processor is further configured to operate the first vehicle and the second vehicle as the series hybrid vehicle when the speed of the second vehicle is greater than a speed threshold.

[0022] The processor is further configured to use data from the second vehicle to determine the speed of the first vehicle if the speed of the first vehicle is not available to the second vehicle.

[0023] In addition to one or more of the features described here, the processor is also configured to determine a trailer coupling force between the first vehicle and the second vehicle.

[0024] The above features and advantages, and further features and advantages of the disclosure, are easily evident from the following detailed description when taken together with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Further features, advantages and details appear only as examples in the following detailed description, which refers to the drawings; they show: Fig. 1 a vehicle 10 according to an exemplary embodiment; Fig. 2 a series hybrid vehicle according to an illustrative embodiment; Fig. 3 a detailed view of a trailer connection cable of the series hybrid vehicle according to an illustrative embodiment; Fig. 4 a schematic representation showing the data flow to the following vehicle during the operation of the series hybrid vehicle according to an illustrative embodiment; Fig. 5 a schematic representation showing various modules or programs that operate the following vehicle during the operation of the series hybrid vehicle according to an illustrative embodiment; Fig. 6 a flowchart of a procedure for operating the series hybrid vehicle according to an illustrative embodiment; Fig. 7 a block diagram illustrating the operation of the fast charging mode; Fig. 8 a block diagram illustrating the operation of a forward coupling algorithm for determining a desired recovery torque in the second vehicle, according to an illustrative embodiment; Fig. 9 a block diagram illustrating the operation of a forward-feedback operating algorithm in the second vehicle according to an alternative embodiment in which a force exerted by the second vehicle on the first vehicle is not directly measurable; and Fig. 10 a series hybrid vehicle according to another illustrative embodiment. DETAILED DESCRIPTION

[0026] The following description is essentially only exemplary. Naturally, corresponding reference numerals in all drawings denote identical or corresponding parts and features. As the term "module" is used here, it refers to a processing circuit arrangement that may include an application-specific integrated circuit (ASIC), an electronic circuit, a processor (shared, dedicated, or grouped), memory that executes one or more software or firmware programs, a combination logic circuit, and / or other suitable components that provide the described functionality.

[0027] Fig. Figure 1 shows an embodiment of a vehicle 10 according to an exemplary embodiment, which includes a vehicle body 12 that at least partially defines an occupant interior 14. Furthermore, the vehicle body 12 supports various vehicle subsystems, including a propulsion system 16 and other subsystems for supporting functions of the propulsion system 16, and other vehicle components such as a brake subsystem, a suspension system, a steering subsystem, and others.

[0028] The vehicle 10 can be an electric vehicle (EV), a hybrid vehicle, or any other type of vehicle. In one embodiment, the vehicle 10 is an electric vehicle that incorporates multiple motors and / or drive systems. It can include any number of drive units, such as one or more drive units for applying torque to the front wheels (not shown) and / or the rear wheels (not shown). The drive units are controllable to operate the vehicle 10 in various modes, such as a normal operating mode, a high-performance operating mode (in which additional torque is applied), all-wheel drive (“AWD”), front-wheel drive (“FWD”), rear-wheel drive (“RWD”), and others.

[0029] The propulsion system 16, for example, is a multi-drive system comprising a front drive unit 20 for driving the front wheels and rear drive units for driving the rear wheels. The front drive unit 20 includes a front electric motor 22 and a front inverter 24 (e.g., a front power inverter module or FPIM), as well as other components such as a cooling system. A left rear drive unit 30L includes a left rear electric motor 32L and a left rear inverter 34L. A right rear drive unit 30R includes a right rear electric motor 32R and a right rear inverter 34R. The front converter 24, the left rear converter 34L and the right rear converter 34R (e.g. power converter units or PIMs) each convert direct current power (DC power) from a high-voltage battery system (HV battery system) 40 into multi-phase alternating current power (e.g. two-phase, three-phase, six-phase, etc.).) Alternating current power (AC power) for driving the front electric motor 22, the left rear electric motor 32L and the right rear electric motor 32R.

[0030] As in Fig. As shown in Figure 1, the drive systems feature separate electric motors. However, embodiments are not limited to this. For example, instead of separate motors, multiple drives can be provided by a single machine having several sets of windings that are physically independent. According to another embodiment, the vehicle can include a single motor that drives the wheels via a conventional final drive.

[0031] As also in Fig. As shown in Figure 1, the drive systems are configured such that the front electric motor 22 drives the front wheels (not shown) and the left rear electric motor 32L and the right rear electric motor 32R drive the rear wheels (not shown). However, embodiments are not limited to this configuration, as there can be any number of drive systems and / or motors in different locations (e.g., one motor driving each wheel, two motors per axle, etc.). Furthermore, embodiments are not limited to a dual drive system, as embodiments can be used with a vehicle with any number of motors and / or power converters.

[0032] In the propulsion system 16, the front drive unit 20, the left rear drive unit 30L, and the right rear drive unit 30R are electrically connected to a battery system 40. The battery system 40 can also be electrically connected to other electrical components (also referred to as "electrical loads") such as vehicle electronics (e.g., via an auxiliary power module or APM 42), heating systems, cooling systems, and other components. The battery system 40 can be configured as a rechargeable energy storage system (RESS).

[0033] According to one embodiment, the battery system 40 comprises several separate battery arrangements, each of which can be charged independently and used to supply power independently to one or more drive systems. For example, the battery system 40 comprises a first battery arrangement, such as a first battery pack 44, which is connected to the front power converter 24, and a second battery pack 46. The first battery pack 44 comprises several battery modules 48, and the second battery pack 46 comprises several battery modules 50. Each battery module 48, 50 contains a number of individual cells (not shown). According to various embodiments, one or more of the battery packs may contain a MODACS battery (multi-output battery with dynamically adjustable capacity).

[0034] Both the front electric motor 22 and the left rear electric motor 32L and the right rear electric motor 32R are three-phase motors with three-phase motor windings. However, the embodiments described here are not limited to this. For example, the motors can be any multi-phase machines fed by multi-phase converters, and the drive units can be implemented using a single machine with independent sets of windings.

[0035] The battery system 40 and / or the propulsion system 16 include a switching system with various switching devices for controlling the operation of the first battery pack 44 and the second battery pack 46 and for selectively connecting the first battery pack 44 and the second battery pack 46 to the front drive unit 20, the left rear drive unit 30L, and the right rear drive unit 30R. The switching devices can also be used to selectively connect the first battery pack 44 and the second battery pack 46 to a charging system. The charging system can be used to charge the first battery pack 44 and the second battery pack 46 and / or to supply power from the first battery pack 44 and / or from the second battery pack 46 to charge another energy storage system (e.g., vehicle-to-vehicle charging (V2V charging) and / or vehicle-to-everything charging (V2X charging)). For V2X charging, power can be used, for example, by...The power can be exported to an external load, to a household (where it acts as reserve power for the household), or to a public power grid. The charging system includes one or more charging modules. For example, a first onboard charging module (OBCM) 52 is electrically connected to a charging port 54 for charging to and from a DC system or DC device external to the vehicle 10 (e.g., DC fast charging or DCFC), such as a utility company's DC power supply. DCFC can be achieved through the charging port 54 and switching devices controlled by the battery control module (e.g., the first OBCM 52) and / or an additional module 66 specific for DCFC communication signals. A second onboard charging module (OBCM) 53 may be included for AC onboard charging, including high-power AC charging or V2X charging.

[0036] According to one embodiment, the switching system includes a first switching device 60, which selectively connects the first battery pack 44 to the front inverter 24, to the left rear inverter 34L, and to the right rear inverter 34R, and a second switching device 62, which selectively connects the second battery pack 46 to the front inverter 24, to the left rear inverter 34L, and to the right rear inverter 34R. The switching system also includes a third switching device 64 (also referred to as a "battery switching device") for selectively connecting the first battery pack 44 and the second battery pack 46 in series.

[0037] Any of several different controllers can be used to control the functions of the battery system 40, the switching system, and the drive units. A controller contains any suitable processing device or unit and can utilize an existing controller, such as a drive system controller, a RESS controller, and / or controllers within the drive system. For example, a controller 65 can be included for controlling switching and drive control operations as discussed here.

[0038] Furthermore, the vehicle 10 includes a computer system 55, which contains one or more processing devices 56 and a user interface 58. The computer system 55 can communicate with the charging system controller to, for example, provide commands to it in response to user input. The various processing devices, modules, and units can communicate with each other via a communication device or system, such as a Controller Area Network bus (CAN bus) or a Transmission Control Protocol bus (TCP bus).

[0039] As shown here, vehicle 10 is an electric vehicle. According to an alternative embodiment, vehicle 10 can be a combustion engine vehicle, a hybrid vehicle, etc.

[0040] Fig. Figure 2 shows the series hybrid vehicle 200 according to an illustrative embodiment. The series hybrid vehicle 200 comprises a first vehicle 202 (lead vehicle) and a second vehicle 204 (follow vehicle), which are generally mechanically coupled for towing and operate synchronously as a single power entity. The first vehicle 202 can be any type of vehicle, such as a gasoline-powered vehicle, a diesel-powered vehicle, an electric vehicle, a hybrid vehicle, etc. The second vehicle 204 is an electric vehicle, such as those found in… Fig. Figure 1 shows that the first vehicle 202 is mechanically coupled to the second vehicle 204 by a trailer hitch 206. The second vehicle 204 is towed by the first vehicle 202 in a flat towing arrangement, in which the wheels of the second vehicle are on the road and rotate during the flat towing operation. A trailer connection cable 208 can be used to provide a communication path between the first vehicle 202 and the second vehicle 204. According to another embodiment, a communication path can be provided via a connection in the trailer hitch 206. According to yet another embodiment, the communication path can be wireless.

[0041] The first vehicle 202 comprises a first drive system 210, a first controller 212, a first sensor system 214, and a first communication device 216. The first drive system 210 controls the transmission of torque from a first drivetrain of the first vehicle 202 to the wheels of the first vehicle. The first controller 212 contains a processor for controlling the operation of the first vehicle 202. The first sensor system 214 comprises one or more sensors for measuring dynamic parameters of the first vehicle 202, which may include, but are not limited to, vehicle speed, engine speed, engine torque, yaw rate of the first vehicle, front wheel road angle, speed of a wheel of the first vehicle, etc. The first sensor system 214 provides the dynamic parameters to the first controller 212.The first controller 212 can control the first communication device 216 to send a signal to the second vehicle 204. As disclosed here, the signal can be used by the second vehicle 204 to control its operation.

[0042] The second vehicle 204 includes a second drive system 220, a second controller 222, a second sensor system 224, and a second communication device 226. The second drive system 220 controls the transmission of torque from a second drivetrain of the second vehicle 204 to the wheels of the second vehicle. The second controller 222 includes a processor for controlling the operation of the second vehicle 204, and the second sensor system 224 may have one or more sensors for measuring dynamic parameters of the second vehicle, which may include, but are not limited to, the vehicle's speed, engine speed, engine torque, yaw rate of the second vehicle, front wheel road angle, speed of a wheel of the second vehicle, etc. The second controller 222 communicates with the second communication device 226.The second communication device 226 is configured to receive a signal from the first communication device 216 and to provide this signal to the second controller 222. Based on this signal, the second controller 222 can perform an operation on the second vehicle 204.

[0043] The first controller 212 and the second controller 222 may include a processing circuit arrangement that may contain an application-specific integrated circuit (ASIC), an electronic circuit, a processor (shared, dedicated, or group), and memory executing one or more software or firmware programs, a combination logic circuit, and / or other suitable components that provide the described functionality. The first controller 212 and the second controller 222 may include a non-transitory, computer-readable medium that stores instructions which, when processed by one or more processors of the first controller 212 and the second controller 222, implement a method for coordinating the operation of the first vehicle 202 and the second vehicle 204 during a towing operation according to one or more embodiments described in detail herein.

[0044] If the first vehicle 202 and the second vehicle 204 are mechanically attached or mechanically coupled, the first vehicle can provide a command or instruction to the second vehicle via the communication channel to control its operation. Thus, the first drive system 210 and the second drive system 220 can operate as a single power entity for the series hybrid vehicle 200. For example, the second vehicle 204 can provide positive thrust when the first vehicle 202 accelerates, which can assist in the acceleration of the first vehicle. Furthermore, the second vehicle 204 can provide deceleration torque when the first vehicle 202 has applied its braking system. In addition, the second vehicle 204 can select to operate in a recuperation mode to charge its battery pack while combined with the first vehicle 202 in the series hybrid vehicle 200.

[0045] Fig. Figure 3 shows a detailed view of the trailer connection cable 208 of the series hybrid vehicle 200 according to an illustrative embodiment. The trailer connection cable 208 includes a lead vehicle coupling 302 and a follow vehicle coupling 304 with wires running between them. The wires include a left-wheel direction indicator wire 306, a right-wheel direction indicator wire 308, a taillight indicator wire 310, and a ground wire 312. When a left turn or left brake is activated on the lead vehicle, a signal is sent via the left-wheel direction indicator wire 306. When a right turn or right brake is activated on the lead vehicle, a signal is sent via the right-wheel direction indicator wire 308. When the lead vehicle's taillights are activated, a signal is sent via the taillight indicator wire 310.

[0046] Fig. Figure 4 is a schematic diagram 400 that illustrates the data flow to the following vehicle during the operation of the series hybrid vehicle 200 according to an illustrative embodiment. The schematic diagram 400 shows the second controller 222 and the second sensor system 224 of the following vehicle. The second sensor system 224 can provide status data of the following vehicle. The schematic diagram 400 also shows lead vehicle data 402, route data 404, and energy map data 406. The lead vehicle data 402 is provided by the first vehicle 202 and includes, but is not limited to, data such as an acceleration request, a braking request, the speed of the lead vehicle, a gear selection or gear state of the lead vehicle, and a braking state of the lead vehicle.

[0047] Route data 404 can be provided by a remote server and includes a route map, weather data, elevation data, and previously learned driving performance data. Route data 404 can be provided for the energy map. The energy map identifies charging stations along the route (e.g., energy map data 406) and provides these locations to the second controller 222. The second controller 222 operates as an Advanced Driver Command Interpreter Module (ADCI 408). The ADCI is a program or application that controls the operation of the following vehicle during a towing scenario and provides torque commands to the following vehicle based on the data provided to the second controller 222.

[0048] Fig. Figure 5 is a schematic representation 500 showing various modules or programs that operate the following vehicle during the operation of the series hybrid vehicle 200 according to an illustrative embodiment. The modules include the ADCI 408, an operating state module 502, a driver command interpreter (DCI) 504, a motor controller 506, a safety limit module 508, a comparator 510, and a display 512.

[0049] The ADCI 408 receives data as it appears in Fig. As shown in Figure 4, the ADCI 408 outputs a desired torque command to be applied to the following vehicle. The desired torque command can be selected to optimize fuel economy and / or the range of the lead vehicle. The operating mode status module 502 provides the ADCI 408 with the current operating mode of the following vehicle (such as actively towing, driving, etc.). The ADCI 408 outputs the desired torque command to the DCI 504 and the safety limit module 508. The DCI 504 determines an engine command for the desired torque. The safety limit module 508 keeps the applied torques within the torque safety limits of the following vehicle. The DCI 504 provides the engine command to the engine controller 506, which applies the engine commands to the engine.The comparator 510 compares the desired torque with the applied torque, with the difference being provided as feedback for the ADCI 408.

[0050] Fig. Figure 6 shows a flowchart 600 of a method for operating the series hybrid vehicle 200 according to an illustrative embodiment. In field 602, the user plugs the trailer connection cable 208 between the first vehicle 202 and the second vehicle 204 and initializes the application that operates the ADCI 408.

[0051] The application can request a profile for the lead vehicle. If the lead vehicle is detected, the profile can be a saved one. Otherwise, a new profile can be created. After the profile has been created, the following vehicle establishes a communication link with the lead vehicle (e.g., via the trailer connection cable 208). The following vehicle then requests a suitable towing mode from the user. Different towing modes give the user flexibility in how their battery is charged while being towed.

[0052] In field 604, the wheels of the second vehicle are disengaged (i.e., its steering lock and parking brake) to allow freewheeling. The second vehicle 204 then flashes its headlights (or provides an audible signal) to indicate to the lead vehicle that the following vehicle is ready to be towed. The second vehicle 204 may display a message on a screen to confirm the selected operating mode. The screen may be a head-up display (HUD).

[0053] In field 606, the second vehicle 204 queries a brake signal from the first vehicle. When the first vehicle 202 applies its brakes, the brake signal is sent. If the brake signal (i.e., a signal along the direction indicator wire 306 for the left wheel and the direction indicator wire 308 for the right wheel) is detected, the process proceeds to field 608. In field 608, the second vehicle 204 enters a braking mode in which braking logic is applied. According to one embodiment, the wheel speed sensors can measure a wheel speed that can be used to select between a regenerative braking mode and an engine braking mode. According to one embodiment, regenerative braking is applied when the state of charge (SOC) of the battery pack is not greater than a specified SOC.

[0054] Returning to field 606, the procedure proceeds to field 610 if no brake signal is detected from the first vehicle 202. In field 610, a taillight signal from the lead vehicle is queried to ensure towing safety. The first vehicle 202 has its headlights on while operating as part of the series hybrid vehicle 200. If a taillight signal is not detected, the procedure proceeds to field 612. No taillight signal (and no brakes) indicates that the first vehicle has been disconnected. In field 612, the second vehicle 204 is placed in a coasting state. The following vehicle may flash its headlights in a selected pattern to signal to the driver of the lead vehicle that the following vehicle is in the coasting state. Returning to field 610, the procedure proceeds to field 614 if a taillight signal is detected.Although the freewheeling decision of field 606 is discussed here as being transmitted by a headlight signal, according to another embodiment any suitable signal (wired or wireless) can be used for communication between the first vehicle 202 and the second vehicle 204 to decide whether the second vehicle enters the freewheeling state.

[0055] Field 614 measures the wheel speed of the second vehicle 204. If the wheel speed v x of the following vehicle smaller than a wheel speed threshold v thres (v x < v thres If ) is the case, the procedure proceeds to field 612. Under this condition, the second vehicle 204 either slows down to reverse (v thres > v x > 0), or does it drive backwards (v x< 0). Thus, the second vehicle 204 is allowed to run freely so that no torque is applied during these movements. Returning to field 614, the procedure proceeds to field 616 if the wheel speed is greater than or equal to the speed threshold value (v). x > v thres ) is.

[0056] In field 616, the following vehicle is configured in a hybrid operating mode. In hybrid mode, the second vehicle 204 provides power to the series hybrid vehicle 200 according to the instructions of the first vehicle 202. The following vehicle mitigates the power expended by the lead vehicle by, for example, providing propulsion according to its own power output and providing braking, etc. Furthermore, the following vehicle can select a charging mode to charge its battery pack based on the movement it provides while being towed. The charging mode can be, for example, a fast-charging mode, a hybrid charging mode, a hybrid maximum mode, and a standard charging mode.

[0057] The fast-charging mode allows the second vehicle (204) to be charged as quickly as possible. This mode includes charging using regenerative braking until the vehicle is fully charged. The charging rate for the battery is related to the vehicle's speed.

[0058] The hybrid charging mode involves maintaining the state of charge (SOC) of the second vehicle's battery pack at a target minimum level. If the SOC falls below this target minimum level, the second vehicle 204 operates in a regenerative braking mode. Otherwise, torque is applied to the second vehicle 204 in a torque-feedback mode.

[0059] The hybrid maximum operating mode prioritizes providing propulsion to the second vehicle 204 until the battery pack's state of charge (SOC) drops to a target minimum level. Apart from the lower target minimum level and the torque-forward coupling operating mode having a higher torque application setpoint, the hybrid maximum operating mode is the same as the hybrid charging operating mode.

[0060] The standard operating mode includes operation in a recuperation mode only when conditions permit, such as when braking is applied to the second vehicle 204.

[0061] When the following vehicle is ready to be unhitched, the user switches off the application, releases the trailer hitch and disconnects the trailer connection cable 208.

[0062] Fig. Figure 7 shows a block diagram 700, which illustrates the operation of the fast-charging mode. The block diagram 700 includes a lookup table 702 and a stability controller 704. The vehicle speed 706 and the battery state of charge (SOC) 708 are entered into the lookup table 702 to output a desired recovery power 710 or an available recovery power. The recovery operation involves ramping up to a maximum recovery power based on the speed of the following vehicle. The maximum recovery rate is limited based on the battery pack's SOC. The desired recovery power 710 is used to determine a desired recovery torque 712. According to one embodiment, the stability controller 704 can be used to determine the desired recovery torque 712 from the desired recovery power 710.

[0063] Fig. Figure 8 is a block diagram 800 illustrating the operation of a forward-feedback algorithm for determining the desired recuperation torque on the second vehicle 204 according to an illustrative embodiment. The forward-feedback algorithm includes a tow-away angle sensor fusion module 802, a vehicle tow resistance estimation module 804, a hybrid torque lookup table 806, and a tow-away stability controller 808.

[0064] A vehicle yaw rate 810, a front wheel angle 812, and wheel speeds 814 of the second vehicle 204 are input into the tow angle sensor fusion module 802, which outputs a vehicle tow angle 816. The vehicle tow angle is an angle between the first vehicle 202 and the second vehicle 204. Determining the tow angle may include an approximate measurement obtained from the first vehicle 202. According to another embodiment, a front camera of the second vehicle 204 may be used to determine the tow angle. The tow angle can be used to limit the torque for safety reasons. For example, the higher the tow angle, the lower the maximum positive torque that can be exerted by the second vehicle 204 on the first vehicle 202.

[0065] Vehicle roll and pitch 818 and vehicle body speed 820 are input into the vehicle drag resistance estimation module 804, which outputs an estimated vehicle drag resistance 822 of the second vehicle. The vehicle drag resistance is useful for estimating the sum of the longitudinal forces acting on the second vehicle, including drag resistance, roll resistance, road gradient, etc. The drag resistance can be calculated using an online machine learning system, a calibrated lookup table, or other methods.

[0066] The vehicle towing angle 816, the estimated vehicle towing resistance 822, the battery's state of charge (SOC) 824, and the vehicle's current hybrid operating mode 826 are entered into the hybrid torque lookup table 806, which outputs a recuperation torque 828. The recuperation torque 828 can optionally be modified by the towing stability controller 808 to determine a desired recuperation torque 830 if additional towing stability is required.

[0067] The energy map data 406 and / or the route data 404 can be provided for the hybrid torque lookup table 806. A decision regarding the recovery torque 828 can be based on the vehicle conditions (e.g., vehicle towing angle 816, estimated vehicle towing torque 822) as well as on the energy map data 406 and / or the route data 404 to provide locations where peak recovery efficiency is necessary and / or where peak load conditions require a given percentage of the free SOC for propulsion purposes.

[0068] Fig. Figure 9 is a block diagram 900, which illustrates the operation of a forward-coupling operating algorithm for the second vehicle according to an alternative embodiment in which a force exerted by the second vehicle 204 on the first vehicle 202 is not directly measurable. The block diagram 900 includes the tow angle sensor fusion module 802, the vehicle drag resistance estimation module 804, the hybrid torque lookup table 806, and the tow stability controller 808. Fig. 8. In addition, the block diagram 900 contains a trailer coupling force estimation module 902, a computing device 904 for the desired trailer coupling force and a torque arbitrator 906.

[0069] The trailer coupling force estimator 902 receives as input the wheel speeds 814 of the second vehicle 204, the vehicle roll and pitch 818, the vehicle body speed 820, and an engine torque 908 of the second vehicle 204. The trailer coupling force estimator 902 calculates a trailer coupling force between the first vehicle 202 and the second vehicle 204 and provides this to the vehicle drag torque estimator 804, which uses the trailer coupling force when calculating the estimated vehicle drag torque 822. The hybrid torque lookup table 806 provides the required torque to the computing unit 904 for the desired trailer coupling force.The desired trailer force computing unit 904 calculates a torque recovery command from the trailer force (from the trailer force estimator) and the specified torque suitable for obtaining the desired trailer force. For example, a trailer coupling pressure force between the first vehicle 202 and the second vehicle 204 is undesirable because it leads to instability. The torque recovery command from the desired trailer force computing unit and the specified torque recovery command from the towing stability controller 808 are input into a torque arbitrator 906, which outputs an engine torque recovery command 908.

[0070] Fig.Figure 10 shows a series hybrid vehicle 1000 according to another illustrative embodiment. The series hybrid vehicle 1000 comprises the first vehicle 202 (lead vehicle), the second vehicle 204 (first follower vehicle), and a third vehicle 1002 (second follower vehicle). The second vehicle 204 is mechanically coupled to the first vehicle 202 for towing, and the third vehicle 1002 is mechanically coupled to the second vehicle 204 for towing. The second vehicle 204 and the third vehicle 1002 are electric vehicles. The trailer connection cable 208 provides a communication path between the first vehicle 202 and the second vehicle 204. A second trailer connection cable 1004 provides a communication path between the second vehicle 204 and the third vehicle 1002. The first vehicle 202 can provide commands or instructions to the second vehicle 204 and to the third vehicle 1002.Thus, the third vehicle 1002 can be operated similarly to the second vehicle 204 during a towing operation. According to another embodiment, additional electric vehicles can be attached behind the third vehicle 1002 and operated similarly.

[0071] The terms "a" and "an" do not denote a limitation of the quantity, but rather indicate the presence of at least one of the mentioned objects. Unless the context clearly indicates otherwise, the term "or" means "and / or." Reference to "an aspect" throughout the patent specification means that a particular element described in connection with the aspect (for example, feature, structure, step, or property) is included in at least one aspect described therein and may or may not be included in other aspects. Furthermore, it should be understood that the described elements can be combined in any suitable way according to the various aspects.

[0072] When an element such as a layer, film, region, or substrate is described here as "on" another element, it may be directly on top of that other element, or there may also be intervening elements. Conversely, when an element is described as "directly on" another element, there are no intervening elements.

[0073] Unless otherwise specified herein, all testing standards are the most recent valid testing standards as of the filing date of this application or the filing date of the earliest priority application in which the testing standard appears, if priority is claimed.

[0074] Unless otherwise defined, technical and scientific terms used herein have the same meaning as they are normally understood by a person skilled in the art in the field to which this disclosure belongs. legend

[0075] In the drawing figures, N stands for no and Y for yes.

Claims

[1] Method for towing a second vehicle (204) by a first vehicle (202), the method comprising: Establishing a communication path between the second vehicle (204) and the first vehicle (202), wherein the first vehicle (202) has a first propulsion system (210); Transmitting a signal indicating an instruction to operate the second vehicle (204) via the communication path from the first vehicle (202) to the second vehicle (204); and Operating a second drive system (220) of the second vehicle (204) together with the first drive system (210) of the first vehicle (202) on the basis of the instruction to operate the first vehicle (202) and the second vehicle (204) as a series hybrid vehicle (200, 1000), characterized by , that The procedure further includes the use of data from the second vehicle (204) to determine a speed of the first vehicle (202) if the speed of the first vehicle (202) is not available for the second vehicle (204). [2] Method according to claim 1, further comprising selecting a charging mode for charging a battery pack (44, 46) of the second vehicle (204). [3] The method of claim 1, further comprising at least one of the following: (i) applying braking to the second vehicle (204) when braking is applied to the first vehicle (202); and (ii) applying torque to the second vehicle (204) in response to an acceleration request from the first vehicle (202). [4] Method according to claim 1, further comprising operating the first vehicle (202) and the second vehicle (204) as the series hybrid vehicle (200, 1000) when a speed of the second vehicle (204) is greater than a speed threshold. [5] Electric vehicle (204), which includes: an electric drive system (220) ; a communication device (226) for communicating along a communication path between the electric vehicle (204) and a first vehicle (202), wherein the first vehicle (202) has a first propulsion system (210), wherein the first vehicle (202) is coupled to the electric vehicle (204) for towing the electric vehicle (204); a processor configured to: Receiving a signal sent from the first vehicle (202) to the communication device (226); Determining an instruction for operating the electric vehicle (204) from the signal; and Operating the electric drive system (220) of the electric vehicle (204) together with the first drive system (210) of the first vehicle (202) on the basis of the instruction to operate the first vehicle (202) and the electric vehicle (204) as a series hybrid vehicle (200, 1000), characterized by , that The processor is further configured to use data from the electric vehicle (204) to determine a speed of the first vehicle (202) when the speed of the first vehicle (202) is not available to the electric vehicle (204). [6] Electric vehicle (204) according to claim 5, wherein the processor is further configured to select a charging mode for charging a battery pack (44, 46) of the electric vehicle (204). [7] Electric vehicle (204) according to claim 5, wherein the processor is further configured to perform at least one of the following: (i) applying braking to the electric vehicle (204) when braking is applied to the first vehicle (202); and (ii) applying torque to the electric vehicle (204) in response to an acceleration request from the first vehicle (202). [8] Electric vehicle (204) according to claim 5, wherein the processor is further configured to operate the first vehicle (202) and the electric vehicle (204) as the series hybrid vehicle (200, 1000) when the speed of the electric vehicle (204) is greater than a speed threshold.

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